1. Field of the Invention
The present invention relates to a communication system comprising at least two peripheral devices, whereby each peripheral device has at least one I/O interface and the peripheral devices are connectable to one another by at least one data bus and exchange data via a communication relationship via the data bus. Further, the invention also relates to an interface device for connecting at least one peripheral device with an I/O interface to a data bus.
2. Description of the Background Art
Communication systems of the aforementioned type have been known for a long time and are used inter alia frequently in control device development and the development of communication systems with the use of control devices. Control device development is also understood to include the development of control device functions in control device hardware invariable per se. Particularly, in the automotive environment, the number of the involved control devices, sensors, and actuators as peripheral devices and the functionalities realized by the hardware increase tremendously and with them the complexity of such communication systems increases greatly. The communication systems in question make it possible first of all that a plurality of peripheral devices are able to communicate with one another, namely can exchange their data in a predefined, and predefinable, manner and are thus able to handle and to realize extensive and networked tasks in distributed systems.
As indicated, peripheral devices may have a very different complexity. Thus, in simple cases, peripheral devices can be a simple sensor, which determines a measured variable and passes it on via the data bus, or it can be an actuator, which converts a datum, a correcting variable, obtained via the data bus into a corresponding output quantity. More complicated peripheral devices can be control devices, therefore “microcomputers,” which handle more complex automation technology tasks independently and are connected via process interfaces, possibly indirectly via other sensors and/or actuators, to the process to be controlled. Further, a peripheral device may be any combination of the described devices. So that these peripheral devices can communicate via their I/O interface by means of the data bus, it is absolutely necessary that the I/O interfaces all meet the standard used as the basis for the data bus overall.
The data bus in many automation technology applications comprises fieldbuses with a completely different specification, which generally comply with a serial data transmission according to the international standard IEC 61158 for “Digital Data Communication for Measurement and Control—Fieldbus for Use in Industrial Control Systems”; it is not a matter of conformity with this standard in the present case, but the fact that all participating peripheral devices must meet a uniform standard is important, so that communication for the purpose of data exchange can occur via the data bus and the I/O interfaces of the peripheral devices. Typical fieldbus standards in the automotive sector are, for example, CAN (Controller Area Network), but time-deterministic serial bus protocols such as TTP (Time Triggered Protocol) or FlexRay are also used increasingly.
Particularly, in the development and the associated testing of automotive systems, the developer faces a number of applications in which the use of a communication system or the adaptation of an existing communication system is virtually not possible or possible only with considerable effort. It occurs, for example, that during the development of a control technology solution to an automation problem, work is performed for a long time not with the peripheral devices that are ultimately used in the series solution, but rather work is performed with peripheral devices in development, which have only part of the equipment of the serial peripheral device, particularly no data bus interface. This scenario is known, for example, from the field of automotive problems, where development control devices are used that do not have the I/O interfaces to be used later in the series solution or that have no I/O interfaces suitable for making a direct connection to a data bus for communication with other peripheral devices.
In other applications, the peripheral devices do have an I/O interface, by means of which a connection to a data bus can be created but this I/O interface is already in use and cannot be employed further for additional tasks. Frequently, an existing communication system should also not be changed as much as possible, existing communication relationships between peripheral devices should not be changed, or this is also not possible because the appropriate development tools are not available.